Ừm , mình nhớ hôm qua bài này , bạn đã đăng rồi và mình cũng đã trả lời cho bạn . Bạn xem lại nhé 

\(n_{Zn}=\dfrac{13}{65}=0,2(mol)\\ a,PTHH:Zn+2HCl\to ZnCl_2+H_2\\ b,n_{HCl}=0,4(mol)\\ \Rightarrow C\%_{HCl}=\dfrac{0,4.36,5}{100}.100\%=14,6\%\\ c,n_{ZnCl_2}=n_{H_2}=0,2(mol)\\ \Rightarrow m_{ZnCl_2}=0,2.136=27,2(g)\\ \Rightarrow C\%_{ZnCl_2}=\dfrac{27,2}{13+100-0,2.2}.100\%\approx 24,16\%\)

Ủa thịnh THCS HTA đúng kh? Này đề thi giữa kì hóa mà thịnh đi hỏi hả ;) tui méc thầy nha

nZn = 13/65 = 0.2 (mol) 

Zn + 2HCl => ZnCl2 + H2

0.2.....0.4.....................0.2

VH2 = 0.2*22.4 = 4.48 (l) 

C M HCl = 0.4 / 0.2 = 2(M)

\(a.\) \(2HNO_3+Ba\left(OH\right)_2\rightarrow Ba\left(NO_3\right)_2+2H_2O\)

\(b.\) \(n_{Ba\left(OH\right)_2}=C_M.V_{dd}=0,15.0,2=0,03mol\)

\(m_{Ba\left(NO_3\right)_2}=0,03.261=7,83g\)

\(c.\)\(n_{HNO_3}=0,03.2=0,06mol\)

\(V_{dd_{HNO_3}}=\dfrac{n}{C_M}=\dfrac{0,06}{1,2}=0,05l\)

\(d.\)\(V_{dd_{spu}}=0,05+0,15=0,2l\)

\(C_{M_{Ba\left(NO_3\right)_2}}=\dfrac{n}{V_{dd}}=\dfrac{0,03}{0,2}=0,15M\)

250ml=0,25l
\(MgO+2HCl\rightarrow MgCl_2+H_2O\)
0.2.........0.4..........0,2............0,2   (mol)
a)
\(n_{MgO}=\dfrac{8}{40}=0,2\left(mol\right)\)
\(m_{MgCl_2}=0,2.95=19\left(g\right)\)
b)
\(C_{M_{HCl}}=\dfrac{0,4}{0,25}=1,6\left(M\right)\)

a/ \(n_{MgO}=\dfrac{8}{40}=0,2\left(mol\right)\)

PTHH: MgO + 2HCl → MgCl₂ + H₂O

Mol:      0,2       0,4            0,2

\(m_{MgCl_2}=0,2.95=19\left(g\right)\)

b/ \(C_{M_{ddHCl}}=\dfrac{0,4}{0,25}=1,6M\)

PTHH: \(CO_2+Ba\left(OH\right)_2\rightarrow BaCO_3+H_2O\)

Ta có: \(n_{CO_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)=n_{Ba\left(OH\right)_2}=n_{BaCO_3}\) \(\Rightarrow\left\{{}\begin{matrix}C_{M_{Ba\left(OH\right)_2}}=\dfrac{0,2}{0,2}=1\left(M\right)\\m_{BaCO_3}=0,2\cdot197=39,4\left(g\right)\end{matrix}\right.\)

CMddBa(OH)2=0,10,2=0,5MCMddBa(OH)2=0,10,2=0,5M

c, mBaCO3=0,1.197=19,7(g)

a, \(CO_2+Ca\left(OH\right)_2\rightarrow CaCO_3+H_2O\)

b, \(n_{CO_2}=\dfrac{5,6}{22,4}=0,25\left(mol\right)\)

\(n_{Ca\left(OH\right)_2}=n_{CO_2}=0,25\left(mol\right)\Rightarrow C_{M_{Ca\left(OH\right)_2}}=\dfrac{0,25}{0,2}=1,25\left(M\right)\)

c, \(Ca\left(OH\right)_2+2HCl\rightarrow CaCl_2+2H_2O\)

Theo PT: \(n_{HCl}=2n_{Ca\left(OH\right)_2}=0,5\left(mol\right)\)

\(\Rightarrow m_{ddHCl}=\dfrac{0,5.36,5}{15\%}\approx121,67\left(g\right)\)

\(n_{CO_2}=\dfrac{5,6}{22,4}=0,25mol\\ a)CO_2+Ca\left(OH\right)_2\rightarrow Ca\left(OH\right)_2+H_2O\)

    0,25       0,25                0,25

\(b)C_{M_{Ca\left(OH\right)_2}}=\dfrac{0,25}{0,2}=1,25M\\ c)2HCl+Ca\left(OH\right)_2\rightarrow CaCl_2+2H_2O\\ n_{HCl}=2n_{Ca\left(OH\right)_2}=2.0,25=0,5mol\\ m_{ddHCl}=\dfrac{0,5.36,5}{15\%}\cdot100\%\approx121,67g\)

`a)PTHH:`

`Mg + H_2 SO_4 -> MgSO_4 + H_2`

`0,2`                                   `0,2`      `0,2`        `(mol)`

`n_[Mg]=[4,8]/24=0,2(mol)`

`b)m_[MgSO_4]=0,2.120=24(g)`

`c)C%_[MgSO_4]=24/[4,8+50-0,2.2].100~~44,12%`

100.\(\approx\)

a, \(Fe_2O_3+6HCl\rightarrow2FeCl_3+3H_2O\)

\(FeCl_3+3KOH\rightarrow3KCl+Fe\left(OH\right)_{3\downarrow}\)

\(n_{Fe_2O_3}=\dfrac{16}{160}=0,1\left(mol\right)\)

Theo PT: \(n_{HCl}=6n_{Fe_2O_3}=0,6\left(mol\right)\)

\(\Rightarrow m_{HCl}=0,6.36,5=21,9\left(g\right)\)

b, \(n_{Fe\left(OH\right)_3}=n_{FeCl_3}=2n_{Fe_2O_3}=0,2\left(mol\right)\)

\(\Rightarrow m_{Fe\left(OH\right)_3}=0,2.107=21,4\left(g\right)\)

\(n_{KOH}=3n_{FeCl_3}=0,6\left(mol\right)\)

\(\Rightarrow C_{M_{KOH}}=\dfrac{0,6}{0,2}=3\left(M\right)\)